Diagnostic testing systems are commonly used to perform various types of diagnostic tests on various types of samples. The diagnostic test may be a qualitative or quantitative test to determine the presence, concentration or amount of one or more analytes in a sample. The analyte may be a medically significant analyte—e.g., glucose, ketones, cholesterol, triglycerides, human choriogonadotropin (HCG), hemoglobin A1C, fructosamine, carbohydrates, tumor markers, lead, anti-epilepsy drugs, bilirubin, liver function markers, toxins or their metabolites, controlled substances, blood coagulation factors (PT, APTT), etc.—contained in a biological sample—e.g., blood, urine, tissue, saliva, etc. However the diagnostic test is not limited to the medical field. For instance, the diagnostic test may determine the presence or quantity of an analyte in a water, soil or chemical sample.
Such diagnostic testing systems may include a test media (e.g., a test strip, tab, disc, etc.) configured to react to the presence of the analyte in a sample, and a separate electronic meter configured to interface with the test media in order to conduct the diagnostic test and indicate the results of the diagnostic test to the user.
In order to conduct the diagnostic test, a user must first obtain a sample test media, e.g., a test strip, from a container, then obtain a sample using a sampling device (e.g., by drawing blood using a lancet), and then apply the sample to the test media (either before or after inserting the test media into the meter interface). The meter then performs the diagnostic test on the sample and indicates the result to the user, e.g., using a numerical display.
However, the diagnostic meter is often bulky. Further, because the user must pick up and put down the test media container, sampling device and meter in succession, the test media container, sampling device and meter are easily separated from each other, so that users may find themselves without one or more of the components necessary to conduct the diagnostic test. Further, it is inconvenient for the user to carry a separate test media container, electronic meter and sampling device.
Further, test media from different brands or manufacturing lots may respond differently to the presence or concentration of analyte in the sample. In order to obtain more accurate results, the electronic meter may be calibrated with respect to a given brand or lot of test strips by providing it with one or more brand- or lot-specific calibration parameters that correlate the response from particular a particular brand or lot of test media to a standardized reference.
The user may be required to provide the meter with the appropriate calibration parameters in a separate “coding” step. For example, the test media container may display a code number from which the meter can determine the appropriate calibration information. The user may then manually enter the code number (e.g., using buttons or other user input devices on the meter) so as to provide the calibration data to the meter. Alternatively, the calibration data may be downloaded, e.g., from a manufacturer's website. In another approach, the test media container may be provided with an associated code chip in which the calibration data is stored electronically. The user may provide the calibration data to the meter by inserting the code chip into a corresponding port on the meter.
This coding step can be inconvenient or difficult for the user. For example, elderly or infirm users may have difficulty downloading calibration data or inserting code chips. Further, users may forget to calibrate the meter for use with a new brand or lot of test media. Consequently, the user may enter incorrect calibration parameters or codes, or the user may use test media from one brand or lot with a meter calibrated for use with test media from a different brand or lot. In addition, once a meter is calibrated for a given lot of test media, the use of that meter with test media from another lot may lead to erroneous results that could have serious consequences for the user. For example, where the test is a self-test of blood glucose level, an erroneous result can misinform the user as to their blood glucose level, which may lead to the user having a diabetic seizure.
A possible solution to the above-mentioned coding problems is utilizing the method of universal coding. This method uses strip lots that are controlled and sorted to a narrow acceptance criteria, i.e. all strips are conformed to a single set of calibration parameters, thus not requiring strip coding or more than one fixed set of strip lot parameters to be stored in the meter 130. Universal coding saves the cost of replacing the meter 130 by allowing it to be used on many different test strip containers 110. In addition, universal coded strips 120 can be tightly controlled such that many strip lots have the same code and are sorted to fit the meter's fixed code assignment. This method is not technique dependent and helps prevent errors due to mixed strip lots. Furthermore, universal coding always has the correct code such that there is no miss-match between the meter 130 and the strip lot code. However, the narrow limits imposed by this method make this an expensive solution as large amounts of waste are generated during the current manufacturing processes.
Accordingly, there is a need for diagnostic testing systems that are convenient to carry and that minimize the chance that a user will use a diagnostic meter with test media from a brand or lot for which the meter has not been calibrated. In addition, there is a need for diagnostic testing systems that reduce the potential for testing a sample with a test meter improperly calibrated for the particular test media used.